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Geography of Fishes

The discipline of geography is one that most people likely dismiss as mapmaking. Gone is the stodgy cartographer and here is the GIS tech wizard. But outside of very particular applications, do most people really give geography a second thought? I hope to show through a famous fishery example that the world should give geography more attention – the Peruvian anchovy fishery.

First a bit of context. Geography is a diverse discipline, spanning applications from environment to physics to cultural anthropology. At the core of the discipline is the importance of place – something very simple yet very often forgotten.

A recent call to education planners to overtly include geography in K-12 curriculum was issued by the American Association of Geographers. The call was placed in response to Obama’s upgrades to education this country and just in time for the AAG’s annual meeting. Obama’s new plans include more specific efforts to tailor school curriculum to the needs of a particular community and, as the call points out “we can argue that geography, of all subjects, is especially suited to adapting to the places it is taught”.

My argument may thus seem like a no-brainer. Place is important, place-based management is inherently a good idea, and education will swing back that direction in no time. But I’d like to give a stark example where geography may have saved the day: the Peruvian anchovy fishery.

Anchovy density used to be astronomical, thanks www.alexanderstubbs.net

Before the crash of the anchovy fishery, there were a number of debates going on about their management. One was about the stock assessments and over whether the population could be modeled well enough in a single species focus or whether multi species models would be more predictive.

At the heart of this argument was the source of the raw data to put into the models. Scientifically produced data by transects and fishery independent surveys were seen as too restrictive in method and unlikely to give you a consistently relevant picture of the fish stock. Fisher knowledge, termed local or traditional knowledge, was seen as too tied to dynamic effort and social factors to give accurate estimates of fish population. Both the scientists and fishers, however, were aware that the fishing had been great for several years and the total allowable catch consequently increased.

However, the side story that no one realized until it was too late, is that the large anchovy stocks that provided for high numbers along the coast of Peru were from a condensed population attracted by cool, nutrient rich upwelling. Fishers had all moved closer to shore to take advantage of this population, but no one had documented the shift in effort. Trawl surveys didn’t pick up on the concentration change because they didn’t travel far enough offshore (likely due to costs associated with offshore monitoring) to pick up the decline in fish stocks farther out.

El Nino related chlorophyll anomalies - the deep purple areas show a severe decrease in productivity, which is measured by chlorophyll concentration representing primary productivity in the system. Thanks to NASA.

El Nino comes along, disrupts the concentration of nutrient rich waters along the coasts, and spreads out the resources over hundreds of miles of open ocean. The fishers can’t catch enough in any one place to be worth the effort, as the small population hammered by years of easy fishing is now spread thin over the new nutrient-rich swath. Scientists suspect the new oceanographic regime can’t support the high production that previously supported the largest fishery in the world. Not only that, overestimates of the population the year El Nino hit led to such drastic overfishing that the stock may never be able to recover.

All because, whether using scientific or traditional knowledge, no one had a good idea of what the spatial components of the fishery were or how a shift in these factors might make a big difference to how many fish could be sustainably caught.

To a large degree, this story is more one of thinking of all the angles of a problem, not one specific to geography. But there is power to thinking of situations in a place-based manner in a more qualitative manner – it helps anchor thinking around something in order to make sure no important angles get missed.

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